COVID-19 has revealed that our human health relies on environmental health. In Marin County, we now have an opportunity to come into alignment with the natural world by using plants to improve the impaired water quality in the Civic Center lagoon. The horrific fish die-off on August 10, 2020, revealed beyond doubt that the waters in the Marin Lagoon need our help!

We are taking an eco-systemic approach. The Gallinas Watershed Council (GWC), with Supervisor Damon Connolly and three students from the Environmental Forum, installed the “floating islands” demonstration in the lagoon during the 2015 Bioneers Conference. The CCWR (Civic Center Watershed Restoration) pilot project has successfully shown how nature itself can improve water quality when allowed to flourish.

The GWC has worked with Marin County Staff, agencies with jurisdiction over the lagoon, local advocates, indigenous cultural practitioners, Traditional Ecological Knowledge (TEK) experts, and neighborhood groups. All the constituents agree that floating ecosystems at scale, with an appropriate selection of native hydrophytes, can provide the biological filtration needed to regenerate the health, well-being, and beauty of the Marin Lagoon and Lagoon Park.

Floating Island Biofilter

Suspended native plants utilize nutrients directly from the water column. Plant roots exude bacteria and enzymes that jumpstart the ecosystem by feeding the base of the food chain. Increased nutrient cycling has helped decrease siltation in stagnant benthic layers and consequently, the need for dredging. In the Marin Civic Center Lagoon, the super-accumulators or plants that could really drive the system are Willows and Tule.

Aurora Mahassine (GWC) & Monique Sonoquie (Indigenous Youth Foundation) display Phase 2 bio-filter.

Aurora Mahassine (GWC) & Monique Sonoquie (Indigenous Youth Foundation) display Phase 2 bio-filter.

How do bio-filters work?

Floating islands cool waters by providing shade and refuge. Native plants, Marin County sourced, sequester carbon and help regenerate both terrestrial and aquatic ecosystems. Plant roots support a robust and complex microbial environment, acting as an incubator for beneficial micro-organisms; arthropods, nematodes, invertebrates, and so on up the food chain. Plants grow by utilizing nutrients in the water while sustaining the healthy functioning of living things.

1-3% of the surface of the Lagoon needs to be covered with floating ecosystems. The increase in habitat for local and migratory wildlife will sustain the lagoon’s beauty and systemic health.

Benefits of bio-filters

  • Reduction and removal of nitrates, phosphates, heavy metals, and organic waste.
  • Movement of nutrients up the food chain, rather than feeding large blooms of algae.
  • Oxygenation: plant roots and living creatures transport oxygen down into the water column.
  • A healthier body of water and a thriving ecosystem, including bigger fish.
Monique Sonoquie, TEK expert weaving a bio-filter layer from Tule

Monique Sonoquie, TEK expert weaving a bio-filter layer from Tule


Frank Lloyd Wright

Having proclaimed himself the world’s first Organic Architect, Frank Lloyd Wright was a 20th-century beacon of green infrastructure. His final opus, the National and State Historic Landmark designs for the Marin Civic Center, Marin Lagoon, and Lagoon Park celebrate the harmony of nature and architecture along with the autopoietic nature of freshwater ecosystems. The cyclical and systemic importance of freshwater is revealed: from the spring-fed, man-enhanced natural lagoon to the fountain on the cafeteria’s garden rooftop; through side water features and interior plantings, and out to the cascades water feature which delivered aeration to the entire recirculating system. Interior trees were planned to provide natural shade, shelter, and air circulation. Transparent roofs were added to the design posthumously and over time the edges of the lagoon have been hardened. 

1957 Frank Lloyd Wright Drawing of Marin County Civic Center Lagoon

1957 Frank Lloyd Wright Drawing of Marin County Civic Center Lagoon

A living edge would be the best ecological solution for the lagoon and reflects Wright’s original design intention. Bioswales could promote infiltration before waste from lawns and pathways contact the water. Floating ecosystems can provide the needed filtration (at 1% to 3% of the surface area of the lagoon) and would not require removal nor addition of concrete.

GWC Lagoon Recommendations

  • Living Edge restoration and removal of concrete that was added against Wright’s design.
  • Bioswales to be installed between the pathways and the lagoon to capture waste.
  • Floating islands, at scale, can replicate the effects of living edges.

Civic Center Lagoon without Living Edge

Gallinas Watershed - Restore Water Quality

Civic Center Lagoon Living Edge

Mockup of Civic Center Lagoon with a Living Edge (courtesy Rebecca Shearin for GWC).

The fish die-off on August 10, 2020, followed after the removal of a significant amount of vegetation from the lagoon including an invasive plant, (Ludwigia peploides), which forms an impenetrable mat on the water’s surface. The GWC recorded unusually high pH and phosphate levels. A biologist from the Fish & Wildlife Services was called in and the Marin County’s Stormwater Pollution Prevention Program (MCSTOPPP) did its own water testing. 

Every year, the lagoon’s water quality decreases with heat, lack of rain, and evapotranspiration. Just as the removal of plants contributed to a fish die-off driven by depleted oxygen, adding native plants should help restore ecological balance and health to this and other impaired waterways. 

Call to Action: Let’s do the Wright thing for the Marin Lagoon!

Now is the time to restore the annually impaired waters of our beloved Frank Lloyd Wright Marin Civic Center Lagoon. 2% of the surface area of the lagoon measures 9,382 sq. ft. of living bio-filters.

Wright’s original drawings show a 90% vegetated edge. Restoring a living edge would help prevent bank erosion and filter the water from excessive nutrient loads.

Let’s start by supporting the collaborations of Biomatrix Water and the Indigenous Youth Foundation and install the 9,382 sq. ft. of floating ecosystems and clean-up the Marin Lagoon! 

Further information:

The GWC has worked exclusively with The Watershed Nursery of Richmond, CA., to ensure only Marin genetics have been introduced throughout our project.